The August 2023 issue explores thermoelectric energy harvesting for converting waste heat to electricity using solid-state devices, presents breakthrough research on enhancing magnesium formability through grain refinement for lightweight automotive applications, and reports on the 13th ISAJ Annual Symposium celebrating 75 years of India's independence.
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Greetings and a warm welcome to this issue of ISAJ Newsletter in 2023! We apologize for our silence since our issue in the last year.
In this issue, we present you with two research articles and event report on 13th Annual ISAJ Symposium-2022. The Research articles are on thermoelectric energy harvesting and room temperature formability of pure magnesium by grain refinement. This issue also contains pictures of our 13th annual symposium held near the end of last year.
Under the Research Spotlight section, we present you an article discussing the concept, challenges and technologies innovations in the field of thermoelectric energy harvesting. This topic is of utmost importance today for environmental conservation. The second research article on room temperature formability of pure magnesium summarizes experimental investigation of grain size impacts on deformation twinning, dislocation slip and grain boundary sliding.
ISAJ organized its 13th Annual Symposium on November 18 (Fri), 2022 in the main auditorium of Embassy of India, Tokyo. The symposium theme was “Frontiers of Materials, Life & Earth Sciences and Beyond”. There were about 90 participants, including 12 plenary speakers, 8 invited speakers and 47 poster presenters.
By Dr. Swapnil Ghodke, Center for Low-temperature Plasma Sciences (cLPS), Nagoya University
Electrical energy plays an essential part in modern human society. Energy is generated by consuming non-renewable resources, which are also responsible for releasing greenhouse gases into the atmosphere. The imbalance in demand and supply of these limited energy resources forecasts a global energy crisis for future generations.
Thermoelectric generators (TEGs) are solid-state devices that can convert waste heat into useful electrical energy without any moving mechanical parts or fluids, emphasized as one of the potential technologies to reduce the carbon footprint and utilize energy resources more efficiently.
When a temperature difference is applied across a substance that easily conducts electricity, such as a metal or semiconductor, a voltage (thermal electromotive force) is generated. The thermoelectric effect represents the mutual influence of thermal and electrical energy.
The efficiency of energy conversion in TEGs is directly proportional to the dimensionless figure-of-merit ZT = S²σT/κ, where:
A high-performance thermoelectric material must be a good conductor of electricity and a poor conductor of heat - a challenging combination since these properties are typically coupled. Strategies for improvement include:
State-of-art materials with ZT > 1:
Space Exploration: NASA utilized TEGs in radioisotope thermoelectric generators for deep space missions and Mars rovers since the 1970s.
Automotive Industry: BMW and others testing TEGs for exhaust heat recovery.
IoT and Wearables: Battery-free devices powered by human body heat for digital watches, health monitoring patches, and autonomous sensors.
The growth of IoT devices has brought TEGs into daily life applications where human body heat generates power for wearable devices. These autonomous power sources for sensors generally do not require large amounts of power and can be sustained from ambient sources.
By Dr. Elango Chandiran, National Institute for Materials Science (NIMS), Japan
Increased greenhouse gas emissions contribute to climate change. Vehicle weight reduction by 10% can lead to 6-8% improvement in fuel economy. Among automotive materials, magnesium offers exceptional promise:
However, room-temperature formability remains inferior to aluminum due to magnesium’s hexagonal crystal structure having only two independent slip systems at room temperature, insufficient for continuous deformation.
Commercially pure magnesium (99.96%) was extruded at temperatures between 100-400°C. Results showed:
Compression testing revealed dramatic differences:
88 μm grain size:
4.8 μm grain size:
Microstructural analysis using SEM and EBSD revealed:
Coarse grains (88 μm):
Fine grains (4.8 μm):
The refinement of grain size by extrusion at lower temperatures effectively realizes higher compressibility and formability of pure magnesium by changing the dominant deformation mechanism from twinning to slip.
The 13th ISAJ Annual Symposium on “Frontiers of Materials, Life, & Earth Sciences and Beyond” was held November 18, 2022, at the Main Auditorium, Embassy of India, Tokyo.
Professor Atsushi Suzuki (Yokohama National University) received the ISAJ Lifetime Achievement Award 2022 for “Bridging between India and Japan researchers to strengthen research collaborations and co-operations in science and technology.”
Wide-ranging topics including:
Winners (20,000 yen each):
Participants expressed strong enthusiasm with suggestions for future improvements. Survey results showed high satisfaction with the scientific quality and organization of the event.
The symposium successfully brought together researchers from prestigious institutions including NIMS, JAMSTEC, Yokohama National University, JAIST, Tohoku University, IIT Delhi, RIHN, Tokyo Institute of Technology, University of Tokyo, University of Tsukuba, AIST, and others.
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Newsletter Details
Volume 8, Issue 1
August 2023
Dr. Swapnil Ghodke
Nagoya University
Dr. Mahendra Kumar Pal
Indian Institute of Technology (BHU), Varanasi
Features research on aquatic bacterial disease prevention using affinity silk filters, IgM-specific antibodies in Medaka for vaccine development, and ISAJ 16th Symposium announcement
Features India-Japan STI Exchange Year, nonlinear optical phenomena in quantum materials, Inconel 718 fatigue modeling, and ISAJ Hokkaido Symposium 2024
Features discovery of SMS inhibitors for fatty liver disease, HAMR magnetic storage technology, and 15th ISAJ Annual Symposium report